Source : Webster's Revised Unabridged Dictionary (1913)

Rhamnus \Rham"nus\, n. [NL., from Gr. "ra`mnos a kind of prickly
   shrub; cf. L. rhamnos.] (Bot.)
   A genus of shrubs and small trees; buckthorn. The California
   {Rhamnus Purshianus} and the European {R. catharticus} are
   used in medicine. The latter is used for hedges.